The Reds selected Kravetz's contract from Triple-A Louisville on Wednesday.
Kravetz, 27, will be making his MLB debut whenever he gets into a game for the Reds. The lefty has made 40 appearances at Louisville this season, logging a 3.43 ERA, 1.45 WHIP and 47:22 K:BB across 42 innings. He'll likely fill a low-leverage role out of the Cincinnati bullpen.